Apparatus for the control of electric lamps



June 24, 1930. A. w. FISHER 1,767,582

APPARATUS FOR THE CONTROL OF ELECTRIC LAMPS Fild July 7. 1921 INVENTOR'.

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Patented June 24, 1930 uNrrEo STATES PATENT OFFICE amnion. w. manna,

RATION OF PENNSYLVANIA FOREST HILLS BOROUGH, PENNSYLVANIA, ASS IGNOR TOTHE UNION SWITCH & SIGNAL COMPANY, OF

SWISSVALE, PENNSYLVANIA, A COB-PO:

APPARATUS FOR THE CONTROL OF ELECTRIC LAMPS Application filed July 7,1927; Serial No. 208,965.

My invention relates to apparatus for the control of electric lamps, andparticularly to lamps which are supplied with current from primarybatteries.

I have found that when a battery, such as that of the caustic soda type,stands on open circuit for a considerable period of time, the batterydevelops the flow of current has continued for a short time. When anelectric lamp is supplied with voltage from a battery of this characterand the circuit is so adjusted that the final or normal voltage of thebattery is the correct voltage for the lamp, the initial voltagesupplied to the lam after the battery has been on open circuit or aconsiderable period of time tends to reduce the life of the lamp. Onefeature of my invention is the provision of means operating when the'circuit for the lamp becomes closed to prevent the supply of excessivecurrent to while the voltage of the battery is dropping to its normalvalue.

I will describe one form of apparatus embodying out the novel featuresthereof in claims.

' The accompanying drawing is a diagrammatic view s owing one form ofapparatus .30 embodying my invention.

Referring to the drawing, the reference character B designates abattery, the voltage of which rises above its normal value when thebattery is on open circuit for a consid- 85 erable period of time. Thisbattery supplies current toan electric lamp L, through a circuit whichincludes a normall of a relay R. The circuit or the relay R, whichcircuit is designated by the reference character'Q, may be controlled inany suitable manner; for example, relay R may be the well known approachlighting relay used in railway signahn systems of the type wherein t esignal am s are normally extinguished and'become ighted upon theapproach of a train.

The circuit for the lamp L also includes an operating windin 3 of .athermostat T havin a normally c osed contact 4 and a norma ly opencontact 5. When the thermoan initial voltage that is considerably higherthan the voltage after the lamp my invention, and will then point;

open contact 8 stat T becomes energized by the supply of current .to itsoperating winding 3, an interval of time elapses during which contact 4remains closed, and after the expiration of such interval of timecontact 4 opens and contact 5 closes. While contact 4 is closed, arelatively high resistance 6 is included in circuit with the lamp L, andwhen contact 5 is closed, a relativel low resistance 7 is included incircuit wit the lamp L;

-The operation of the apparatus is as follows: Assuming that contact 8of relay R has been opened for a considerable period of time, contact 4of thermostat T will be closed, so that when contact 8 closes, therelatively high resistance 6 will be included in series with the lamp L,andthis resistance prevents the supply of an excessive amount of currentto the lamp L while the voltage of battery B is dropping to its normalvalue. After the lapse of aperiod of time sufficient to enable thevoltage of battery B to reach its normal value, contact opens andcontact 5 closes, thereby removing the high resistance 6 from thecircuit of lamp L and insertin the low resistance 7 in this circuit. Thebig 1 resistance 6 therefore prevents shortening of the life of the lampL due to the excessive voltagede'veloped by the battery B for a shortperiod of time after the circuit forthe lamp becomes closed at contact8.

' I have referred to the resistance 7 as hav- Although I have hereinshown and described only one form of apparatus embodying my invention,it is understood that various changes and modifications may be madetherein within the. scope of the appended claims without departmg fromthe spirit and scope of my invention.

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Having thus described my invention, what claim is:

1. In combination, a source of electric current the voltage of whichrises above its nor- 5 mal value when on open circuit for a considerableperiod of time, an electric lamp, a normally open circuit including saidsource and said lamp, a slow acting thermostatic circuit controllerhaving a winding included in said circuit, and means controlled by'saidcircuit controller for preventing the supply of excessive current tosaid lamp when the circuit becomes closed and for subsequently reducingthe resistance of the circuit.

2. In combination, a source of electric current the voltage of whichrises above its normal value when on open circuit for a considerableperiod oftime, an electric lamp, a normally open circuit including saidsource so and said lamp, a thermostat included in said circuit, andmeans controlled by said thermostat for permitting the supply of normalcurrent but preventing the sup ly of excessive current to said lampafter tlie circuit becomes closed and while the voltage of said sourceis dropping to its normal value.

3. In combination, a source of electric current the voltage of whichrises above its normal value when on open circuit for a considerableperiod of time, an electric lamp, a

thermostat having a winding and a normally closed contact and a normallyopen contact, a normally open circuitincluding said source and said lampas well as said nor- 85 mally closed thermostat contact and aresistance, and an auxiliary circuit including said source and said lampas well as the normally open contact of said thermostat but excludingsaid resistance.

4o 4. In combination, a source of electric current the voltage of whichrises above its normal value when on open circuit for a con siderableperiod of time, an electric lamp, a normally open circuit including saidsource and said lamp, a thermostat having a winding included in saidcircuit, and means controlled by said thermostat for reducing theresistance of said circuit after the circuit has been closed long enoughto allow the voltage of said source to drop to its normal va ue.

In testimonywhereof I afiix m si ature.

AR W. F IS R.

